Complications

An arteriovenous fistula (AVF) may give rise to the following complications:

• infection
  • responsible for 20%of all AVF related complications
  • the severity may vary from localised cellulitis (erythema and heat) to abscess formation (fluctuance and tenderness) and bacteraemia (pyrexia, rigors, and feeling unwell)
  • screen patients using microbiological swabs and serum samples for
    • meticillin resistant Staphyloccocus aureus
    • vancomycin resistant enterococci
    • extended spectrum β lactamase producing organisms
  • if AVF becomes the source of recurrent septic emboli, surgical closure may be required
• thrombosis
  • can be due to pre-existing or acquired anatomical lesions, stenosis, hypercoagulability, and compression of the fistula.
  • antiplatelets may be beneficial during the early postoperative period (when the risk of thrombosis is high)
• stenosis
  • stenosis describes the narrowing of the lumen for more than 50% and is the most common cause of late failure of fistulas
  • if caused during the first month of creating the AVF, technical error is the usual cause
  • assess for evidence of stenosis (can be carried out in the clinic or by the patient at home)
    • have the fistula arm dependent with the fist close
    • observe for the filling of the vein
    • slowly raise the arm – the AVF should collapse in the absence of a stenosis
    • if a section of the AVF has not collapsed, the stenosis lies at the junction
  • preferred treatment of choice is percutaneous angioplasty
• aneurysm
  • may occur as a natural process with time due to increase in blood flow
  • evidence of overlying skin changes and ulceration (indicates increased risk of rupture and severe haemorrhage) may warrant surgical repair
• ischaemic polyneuropathy
  • patient may present with paraesthesia, dysaesthesia, severe pain, and muscle weakness
  • more common in pre-existing diabetes and peripheral vascular disease (when AVF is created using brachial artery)
• Steal syndrome
  • seen in 8% of the patients receiving haemodyalisis but the rate increases to 75-90% in elderly patients, patients with diabetes and peripheral vascular disease
  • patients may present with
    • considerable pain
    • a cold hand, and discoloration of the skin due to relative hypoperfusion of the extremity
    • weak or absent pulse
    • with time neuropathic features may develop resulting in a typical “claw hand” contracture.
• high output cardiac failure
  • caused by shunting of arterial blood from the left to right sided circulation
  • cardiac output is estimated to be increased by 15% and end diastolic ventricular pressure by 4%
  • risk of developing high output cardiac failure is higher when the AVF is proximal
  • patients will have typical cardiac failure symptoms - dyspnoea and peripheral oedema
• limb hypertrophy in children - result from congenital fistulae. The whole of the limb is increased in length and volume, with the skin warmer and pinker than the normal side

Reference:

• (1) Siddiky A et al. Management of arteriovenous fistulas. BMJ. 2014;349:g6262
• (2) Nagpal K, Ahmed K, Cuschieri R. Diagnosis and management of acute traumatic arteriovenous fistula. Int J Angiol. 2008;17(4):214-6